HEPES

From OpenWetWare

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
N-(2-hydroxyethyl)piperazine-N’-(2-ethanesulfonic acid); 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; CAS NUMBER: 7365-45-9
N-(2-hydroxyethyl)piperazine-N’-(2-ethanesulfonic acid); 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; CAS NUMBER: 7365-45-9
-
A Good buffer <cite>Good66</cite><cite>Good74</cite><cite>Blanchard84</cite>.  Stable pH vs. temperature, no amine groups, no metal chelation, near physiologic pH range.
+
A Good buffer <cite>Good66</cite><cite>Good74</cite><cite>Blanchard84</cite>.  Stable pH vs. temperature, no primary amine groups, no metal chelation, near physiologic pH range.
* pK<sub>a</sub> at 25C of 7.55 (7.31 at 37C)
* pK<sub>a</sub> at 25C of 7.55 (7.31 at 37C)
Line 8: Line 8:
* molecular weight 238.3
* molecular weight 238.3
* &Delta;pK<sub>a</sub>/&Delta;T = -.014
* &Delta;pK<sub>a</sub>/&Delta;T = -.014
 +
*HEPES contains tertiary amines, which are reactive under certain conditions. See its structure in the [http://www.sigmaaldrich.com/catalog/search/ProductDetail/SIGMA/H3375 Sigma catalog].
 +
*Chemical formula: C<sub>8</sub>H<sub>18</sub>N<sub>2</sub>O<sub>4</sub>S
Buffers are typically 1 M, prepared by neutralizing HEPES with sodium hydroxide.  HEPES is essentially insoluble until it is neutralized.
Buffers are typically 1 M, prepared by neutralizing HEPES with sodium hydroxide.  HEPES is essentially insoluble until it is neutralized.

Revision as of 11:52, 5 May 2006

N-(2-hydroxyethyl)piperazine-N’-(2-ethanesulfonic acid); 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; CAS NUMBER: 7365-45-9

A Good buffer [1][2][3]. Stable pH vs. temperature, no primary amine groups, no metal chelation, near physiologic pH range.

  • pKa at 25C of 7.55 (7.31 at 37C)
  • a second pKa at pH 3 is not of interest
  • usable buffering range of 6.8 to 8.2
  • molecular weight 238.3
  • ΔpKa/ΔT = -.014
  • HEPES contains tertiary amines, which are reactive under certain conditions. See its structure in the Sigma catalog.
  • Chemical formula: C8H18N2O4S

Buffers are typically 1 M, prepared by neutralizing HEPES with sodium hydroxide. HEPES is essentially insoluble until it is neutralized.

  1. Good NE, Winget GD, Winter W, Connolly TN, Izawa S, and Singh RM. . pmid:5942950. PubMed HubMed [Good66]
  2. Good NE and Izawa S. . pmid:4206745. PubMed HubMed [Good74]
  3. Blanchard JS. . pmid:6717292. PubMed HubMed [Blanchard84]
All Medline abstracts: PubMed HubMed
Personal tools